The present invention relates to an improvement of an ion plating device, and more particularly to a high vacuum ion plating device characterized in that an electron shower is applied to the evaporated particles that are moving towards the body to be plated. The particles are generated from an evaporation source whereby the particles are ionized.
Ion plating devices which have been employed conventionally are constructed in such a manner that an evaporation source and a body to be plated are disposed in an evaporation chamber in which an inert gas such as Ar, He and the like is sealed under pressure of about 10.sup..sup.-1 to 10.sup..sup.-2, torr and a DC voltage is impressed between them so that the inert gas is excited by the DC voltage to generate a glow discharge. The particles of an evaporation material being evaporated from the evaporation source are ionized by the glow discharge and then are accelerated in a DC field formed by impression of a DC voltage. The particles are caused to collide with and adhere to the body to be plated.
In the ion plating method mentioned in the foregoing, the particles of evaporated material are ionized and are accelerated in the DC field. Therefore a film formed on the surface of the body to be plated has a high degree of adhesion as compared with a film obtained by ordinary vapor deposition methods. Also, in ion plating, it is possible to select a wide rang of evaporation source materials and materials to be plated.
However, in the conventional ion plating device mentioned in the foregoing, the glow discharge for ionizing the evaporated particles is generated between the evaporation source and the body to be plated. Therefore the body to be plated is not only subjected to the collision of the particles of the evaporated material but also to the collision of the inert gas which is ionized, causing elevated temperatures so that the temperature control of the body to be plated is difficult. Accordingly, it has been almost impossible to use a material having a low heat resistance as the body to be plated. Also, depending upon the conditions during the evaporation process, back sluttering occurs which results in a tendency of generating defects on the film, and moreover the structure and characteristics of the film formed thereby have not necessarily been satisfactory.